Long-term follow-up demonstrated that the efficacy of imatinib persistent over time without unacceptable cumulative or late toxicities among patients with chronic myeloid leukemia (CML), according to a study published in The New England Journal of Medicine.1

Although the clinical activity and safety of imatinib are well documented, long-term outcomes of the drug remain less clear. Researchers evaluated the efficacy and safety of imatinib used as initial therapy after 10 years of follow-up.

The international, open-label, phase 3 IRIS study (ClinicalTrials.gov Identifiers: NCT00006343 and NCT00333840) randomly assigned 1106 patients with newly diagnosed CML in chronic phase 1:1 to receive single-agent imatinib or interferon alfa plus cytarabine.

Median follow was 10.9 years. Patients initially randomized to the imatinib arm had an estimated 10-year overall survival rate of 83.3% (95% CI, 80.1-86.6). Nearly half of the patients assigned to receive imatinib completed study treatment with imatinib, and 82.8% achieved a complete cytogenetic response at the end of the trial.

The estimated rate of event-free survival at 10 years was 79.6% (95% CI, 75.9-83.2) among patients randomly assigned to imatinib compared with 56.6% (95% CI, 51.5-61.6) of patients assigned to receive interferon alfa plus cytarabine arm.

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Investigators observed serious adverse events in 9.3% of the evaluable 551 patients treated with first-line imatinib. These events occurred most often during the first year of treatment and declined over time. Additional follow-up showed no new safety signals.

Reference

  1. Hochhaus A, Larson RA, Guilhot F, et al. Long-term outcomes of imatinib treatment for chronic myeloid leukemia. N Engl J Med. 2017;376:917-927.